Federal Defense of Marriage Act (DOMA)

In 1996, Congress adopted the federal Defense of Marriage Act (DOMA). Pub. L. 104-199, 100 Stat. 2419 (Sept. 21, 1996). Congress passed DOMA because of a decades-long assault on marriage, and particularly in response to a Hawaii court decision that suggested there is a right to same-sex “marriage” in the Hawaii Constitution. The legislative history reflects a congressional concern about the effect that legalizing same-sex “marriage” in Hawaii would have on other states, federal laws, the institution of marriage, traditional notions of morality, and state sovereignty. H.R. Rep. No. 104-664 at 1-18 (1996), reprinted in 1996 U.S.C.C.A.N. 2905-23.
DOMA has two sections, one defining “marriage” for purposes of federal law, and the other affirming federalism principles under the authority granted by Article IV, Section 1 of the Constitution, the Full Faith and Credit Clause. The first section states that for purposes of federal law, marriage means a legal union between a man and a woman:

In determining the meaning of any Act of Congress, or of any ruling, regulation, or interpretation of the various administrative bureaus and agencies of the United States, the word “marriage” means only a legal union between one man and one woman as husband and wife, and the word “spouse” refers only to a person of the opposite sex who is a husband or a wife.

Pub. L. 104-199, sec 1, 100 Stat. 2419 (Sep. 21, 1996), codified at 1 U.S.C. § 7 (1997). The second section reaffirmed the power of the states to make their own decisions about marriage:

No State, territory, or possession of the United States, or Indian tribe, shall be required to give effect to any public act, record, or judicial proceeding of any other State, territory, possession, or tribe respecting a relationship between persons of the same sex that is treated as a marriage under the laws of such other State, territory, possession, or tribe, or a right or claim arising from such relationship.

Legislative History

DOMA was signed by President Clinton on Sept. 21, 1996, becoming Pub.L. 104-199, 110 Stat. 2419, codified at 1 USC 7 and 28 USC 1738C. It passed the Congress as H.R. 3396.
DOMA passed the U.S. House on July 12, 1996, by a vote of 342-67 (vote no. 316). Floor statements on the bill will appear in the Congressional Record of that day. House hearings on DOMA were held on May 15, 1996, in a subcommittee of the Judiciary, Committee on the Constitution. The leading legislative record is the House Report, No. 104-664. The hearing before the subcommittee can be found here.
DOMA passed the U.S. Senate, unamended, on September 10, 1996, by a vote of 85 to 14 (vote no. 280). The Senate Judiciary Committee held hearings on July 11, 1996 (on the bill S. 1740), and they were printed as Senate Hearings 104-533.